Portable device with apertured electrical contacts

ABSTRACT

The invention relates to a portable electronic device comprising a supporting member receiving on one side conductive contact lands or tracks extending substantially as far as the edge of the side and connecting an electronic microcircuit, the conductive contact lands or tracks comprising a plurality of perforations. The device is noteworthy in that the interior of the perforations is free, or intended to be kept free, of metal.

FIELD OF THE INVENTION

The present invention relates to chip card portable devices and a methodfor producing such devices.

In particular, it relates to portable electronic devices comprising asupporting member, a rear side of which receives an antenna connectingan electronic microcircuit and a side comprising contact lands at leastpartially extending as far as the edge of the side.

These electronic devices can more particularly be found in electroniclabels and contactless chip cards, contact and contactless hybrid chipcards provided with an electronic module.

A common but by no means restricting standard for the present inventionis the so-called ISO 7810 standard which concerns a card having astandard format, i.e. 85 mm in length, 54 mm in width and 0.76 mm inthickness. The contacts are defined by the 7816 standard particularly asregards the positioning and extent thereof.

STATE OF THE ART

The applicant's patent application EP 1 492 148 A2 is known, whichdescribes the principle of an antenna module comprising a substrate, therear side of which carries a flat wound radiofrequency antenna and thefront side of which carries contact lands for communicating with acontact reader.

Patent EP 1031939 (B1) is also known, which describes a hybrid type chipcard with improved radiofrequency performances. It describes a card withan antenna module of the type above magnetically coupled with a relayantenna arranged in the card body.

Patent FR2765010 (B1) also describes a dual interface antenna module.The antenna is arranged on the periphery of the electrical contacts toavoid a radiofrequency waves barrier formed by the contact lands andthus to improve the radiofrequency communication. The electromagneticpermeability of the module is thus improved.

The patent application US2009/0271972 describes a contactless chip cardusing a contactless chip module comprising perforated connection lands.These lands are pre-perforated or perforated during a sewing operationusing a sewing needle. These perforations contain a metallic antennawire which remains inside the perforations when the antenna is connectedto the connection lands.

Patent application EP 1932104 (A1) shown in FIG. 1 also describes anantenna module 11 coupled with a relay antenna in a chip card comprisingmeans for improving the magnetic permeability. It teaches placing theantenna on the periphery of the contact lands 19 on the rear sideopposite the one carrying the contact lands and placing on the peripheryand outside the contact lands, a plurality of protrusions 33substantially extending from the lands to the periphery of the module.In addition to providing electromagnetic permeability, such positioningcontributes to distribute a module bonding pressure in a chip card bodycavity during the module inlay phase.

The protrusions may be obstacles and/or cause wear of some readersconnectors when the card is inserted into the reader slot.

The invention aims to avoid the above drawbacks.

The present invention also provides a module construction enabling areduction in the production costs while maintaining the electromagneticpermeability performances relative to a radiofrequency communicationantenna more particularly according to the ISO/IEC 14443 standard.

The principle of the invention mainly consists in designing contactlands, apertured electric tracks or positioning perforations calibratedup to a maximum, on such metal parts outside the standardized areas.

To this end, the invention relates to a portable electronic devicecomprising a supporting member receiving on one side conductive contactlands or tracks extending substantially as far as the edge of the sideand connecting an electronic microcircuit, with the conductive contactlands or tracks comprising a plurality of perforations, characterized inthat the interior of said perforations are free, or intended to be keptfree, of metal.

According to other characteristics:

-   -   A rear side of the supporting member comprises an antenna formed        by a plurality of turns comprising two connecting ends and in        that the plurality of perforations form areas of magnetic        permeability for the antenna,    -   The perforations are positioned on the periphery of the device        and/or at the centre, with the antenna being positioned at least        partly substantially facing the magnetically permeable areas;    -   The perforations are positioned arranged on the path (F) of the        contact lands of an electrical contact reader connector when the        device is inserted into the slot of a reader;    -   The width of the contact lands is reduced toward the edge of the        supporting member.

DESCRIPTION OF THE FIGURES

The invention will be better understood while referring to the followingdescription given by way of non-restricting example, and to the appendeddrawings, wherein:

FIG. 1 shows a module for contactless chip card according to the stateof the art

FIG. 2 shows a cross section of a contact card module according to anembodiment of the invention;

FIG. 3 shows a cross section of a module for a hybrid contactless cardaccording to a second embodiment of the invention;

FIG. 4 shows a cross section of an antenna module for a hybridcontactless card according to a second embodiment of the invention;

FIGS. 5 to 8 show a top view of alternative embodiments of the contactlands of an electronic module according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Similar elements are designated by the same reference numbers in all thefigures.

In FIG. 2, a portable electronic device 20 comprises a supporting member21 and a side 22 of the supporting member having contact lands 23extending at least partially as far as the edge of the side 24. Theselands are electrically connected to an electronic microcircuit 45.

In the present example the device is a smart card with electricalcontacts and the supporting member is an electronic module insulatingsubstrate 20 for a chip card. The module is inlaid in a chip card body25. Alternately, the device may be the module itself.

According to a characteristic of an embodiment, conductive contact landscomprise a plurality of perforations 27.

In the case of chip cards, the perforations may be localized in areas25, 26 different from the standardized contact lands C1-C8 (FIG. 5-8).

In the example, a plurality of perforations are circles but may haveother geometric shapes.

The total of the removed surfaces must be sufficient to really enablesaving on materials such as gold, palladium, nickel . . . while ensuringsufficient rigidity to meet the reliability requirements of the obtainedproducts for example of the micro-module type.

The perforations are made during the manufacturing of the film bychemical etching or mechanical cutting at the same time as the contacts.

Holes, 300 μm in diameter, seem to be a good compromise with respect tothe contact surfaces of the connectors and the mechanical resistance toflexion/torsion tests thanks to the module rigidity: no stairstepeffect, no weakening of the electronic part. Preferably, the holes maybe between 250 and 350 μm in diameter or have an equivalent surface.

However, this dimension may vary depending on the desired model and onthe technological developments by the providers of the so-called “leadframe” module substrate (a substrate comprising or supporting contactlands).

The module may be cut in copper or in the dielectric supporting film toavoid corrosion. In the latter case copper is not exposed on the edgethereof, which limits corrosion phenomena. The space between the edge ofthe module and the electric areas may however be small enough not tocreate a stairstep effect or for the card reader connectors.

There is no risk of flow of the resin (bonding of the chip,encapsulation resin . . . ) during the assembly if it is deposited on anarea where the dielectric is solid or if not so (in case of a centralwindow, of weld zones) on an area where no perforations are provided incopper.

The perforations may be made anywhere outside areas C1-C8 defined by theISO 7816 standard or partially (e.g. on the contact lands but not on theframe or vice versa, see FIGS. 5-8). The perforations may be limited oncertain areas of the contact lands.

In FIG. 3, the module is a module for combination (or dual interface)card, wherein the antenna is positioned in a card body like 25 (notshown). The module here has metallizations 28 on both sides 25 and 35.These metallizations may also be perforated.

In FIG. 4, the module is an antenna module. It receives, on the rearside, an antenna 29 formed of a plurality of turns 30 having twoconnecting ends 31. These ends 31 are connected to lands of theelectronic chip.

Advantageously, the perforations form magnetic permeability areas forthe antenna.

The perforations may be arranged on the periphery of the device and/orat the centre (FIG. 7). The turns of the antenna are arranged at leastsubstantially partly opposite such magnetically permeable zones.

According to one characteristic of the invention, the perforations arearranged outside a path (arrow F) of the contact lands of an electricalcontact reader connector when the device is inserted into the slot of areader.

The perforations are positioned on the periphery of the device or at thecentre thereof, and the turns are positioned substantially opposite themagnetically permeable zones.

The invention may relate to any form of a module wherein a number 6, 8of contact lands is required (Other module types (plug-in combination),single-sided, double-sided of the combination type, antenna module andany new application having a side with electrical contacts.

The electrical contact lands in the form of parallelepipeds are known(see FIG. 5), but these may have other shapes that still enable acorrect “lead” of the contact to the connectors.

In particular, as shown in FIG. 8, the width 46 of the lands is reducedtoward an edge 24 at least corresponding to the edge of introductioninto a reader. The edges of the contacts, for example substantially havethe shape of a “V”. The tip of the V is substantially centred on thepath of the connectors upon insertion into the reader.

Thus, this “V” shape makes it possible to clear magnetic permeabilityzones 47 between contact lands adjacent to one another.

Advantageously, the contact lands contain no perforation or a minimum ofperforations arranged on the rectilinear path F of the reader connectorswhich is perpendicular to an edge 24 of the module.

Thus, the connectors always slide on substantially solid portions 49made of conductive material, thus avoiding premature wear of theconnectors and/or the contact lands.

In FIG. 5, the contact lands 23 extend as far as the edge of the module.The dielectric substrate 21 has a larger area S1 in the upper S1 andlower S2 part of the module.

The central part S3 between the zones C1-C8 has no metal surface either.

In FIGS. 6 and 7, the surfaces S1, S2, S3 referred to above are providedwith parts P1-P5 comprising perforated metal. The advantage of theseparts is to avoid steps for connectors but also to foster a correctdistribution of bonding pressure on the module upon attachment thereofin a card body cavity and/or rigidity of the module.

The device may relate to a radiofrequency token of the RIFD type with aUSB drive having or not a radiofrequency function, any integratedcircuit chip electronic device having conductive tracks with a minimumsurface more or less imposed by its function. The perforations make itpossible to save 20 to 50% of metal as compared to the electricalcontacts without reducing their electrical function or mechanicalstrength.

The conductive tracks or connections lands on the back of the module(FIG. 3) may also be perforated.

The metallizations may receive or comprise a partial or full insulatingfilling (resin or any other insulating material, e.g. plastics) whichenables perforations with larger widths, e.g. above 350 μm, for examplebetween 350 μm and 1,000 μm or more: 3,000 μm, while avoiding theproblem of steps (or greater) above with respect to a reader connector.The module may also be reinforced by such perforations filling.

The perforations are free, and kept free, of metal or electricallyconductive material at least inside, more particularly for savingpurposes or for achieving magnetic permeability.

The metallizations may be free of metal or be formed with recesses uponproduction thereof.

The perforations may have other shapes such as for example zigzags,straight or curved slots, waves.

Any total or partial obstruction inside the perforations or oppositethese perforations is thus excluded a priori. Exceptionally, antennaturns may be arranged opposite the perforations for achieving magneticpermeability, if need be (not only connection ends like documentUS2009/0271972).

The turns are preferably arranged on a side of a substrate (or asupporting member) opposite the one carrying the metallizations.

1. A portable electronic device comprising a supporting member receivingon one side conductive contact lands or tracks extending substantiallyas far as the edge of the side and connecting an electronicmicrocircuit, with the conductive contact lands or tracks comprising aplurality of perforations, wherein the interior of said perforations isfree, or intended to be kept free, of metal.
 2. A portable electronicdevice according to the previous claim 1, wherein a rear side of thesupporting member comprises an antenna formed of an assembly of turnscomprising two connecting ends and wherein the plurality of perforationsform areas of magnetic permeability for the antenna.
 3. A portableelectronic device according to claim 2, wherein the perforations arepositioned on the periphery of the device and/or at the centre, with theantenna being positioned at least partly substantially facing themagnetically permeable areas.
 4. A portable electronic device accordingto claim 1, wherein the perforations are positioned on the path of thecontact lands of an electrical contact reader connector when the deviceis inserted into the slot of a reader.
 5. A portable electronic deviceaccording to claim 1, wherein the width of the contact lands is reducedtoward the edge of the supporting member.
 6. A portable electronicdevice according to claim 1, wherein the diameter of the perforationsranges from 250 to 350 μm.
 7. A portable electronic device according toclaim 1, wherein the device comprises or constitutes a chip card module,with the contact lands complying with ISO 7816 standard or a USB drive.